Cactus Wrens, which may nest several times between March and September, carefully orient their nests in tune with the season. These bulky twig structures have a side entrance that curves toward the inner chamber. When building a nest for the hot months, the wren faces the opening to…

Green-winged Teal are North America's smallest dabbling duck, at just over a foot long and weighing less than a pound. The male has a cinnamon brown head with a band of green behind the eye. Both males and females have a green bar on the wing that gleams like an emerald when the sun…

The eerie sound of the Great Tinamou can be heard in the lowland jungle throughout much of Central and South America. Secretive — and almost impossible to see — Great Tinamous call early and late in the day. And their voices carry a long distance.

When Cliff Swallows arrive on the breeding grounds in North America, the dirty work begins. The swallows scoop up mud in their beaks and carefully build a gourd-shaped nest with a tapered opening. They add a lining of dry grass to keep eggs warm. It takes days of work and a thousand…

Aplomado Falcons were once widespread residents of the American Southwest, but by the 1950s, they'd disappeared entirely from the region. Loss of habitat, loss of prey, and pesticides all played a role. But in the 1980s, a group called The Peregrine Fund began breeding captive Aplomado…

A hummingbird's brilliant throat feathers are called a "gorget," a term applied in past centuries to the metallic swatch protecting the throat of a knight-in-armor. Light waves reflect and refract off the throat feathers, creating color in the manner of sun glinting off a film of oil on…

The asteroid that struck the Yucatán 66 million years ago wreaked worldwide ecological damage, spelling the end for most dinosaurs and destroying the world’s forests. Yet a few bird-like dinosaur groups made it through. Scientists believe that these groups were all ground-dwellers. Though…

The White-tailed Hawk thrives in the grassy plains of the Texas Coastal Plain, where many tropical species reach the northern limit of their ranges. White-tailed Hawks often hunt by kiting: hovering like a kite in the breeze with the wings held in a “V” above the body, dropping suddenly on…

Beavers are well known as ecosystem engineers in North America. In Australia, lyrebirds play a big role in shaping their environment when they use their toes to dig in the ground for food. A single lyrebird can shift 11 dump truck loads of soil and leaves — each year! That’s thought to be…

House Wrens dart from perch to perch and sing almost nonstop. They’re one of the most thoroughly studied songbird species. House Wrens nest in cavities, including backyard nest boxes. Most migrate south in late summer. The male House Wren sometimes builds multiple nests, allowing his mate…